[SOLVED] Steam Online Subsystem is being blocked by some process

Hi,
I am trying to set up a network game using SteamOnlineSubsystem (using app id 480 - “spacewar” ) and SteamVR.
My colleague is using a Vive and myself a Oculus headset.

Everything worked fine a couple of months ago (using UE 4.16) We were able to connect to each other’s sessions and interact.

Now after a couple of months development pause we upgraded to UE 4.18 and suddenly no sessions can be found anymore. While trying to narrow down the problem we also started the old 4.16 builds and ran into the same issue. The same builds that were running smoothly a couple of months ago couldn’t find our mutual sessions anymore.

My logs are throwing this warning now:

LogOnline: Display: STEAM: Loading Steam SDK 1.39
LogOnline: STEAM: Steam User is subscribed 1
LogOnline: STEAM: [AppId: 480] Client API initialized 1
LogOnline: Verbose: STEAM: Initializing Steam Game Server IP: 0x00000000 Port: 7777 SteamPort: 7778 QueryPort: 27015
LogOnline: STEAM: [AppId: 480] Game Server API initialized 0
LogOnline: Warning: STEAM: Failed to initialize Steam, this could be due to a Steam server and client running on the same machine. Try running with -NOSTEAM on the cmdline to disable.
LogOnline: Display: STEAM: OnlineSubsystemSteam::Shutdown()
LogOnline: Warning: STEAM: Steam API failed to initialize!
LogOnline: Display: STEAM: OnlineSubsystemSteam::Shutdown()
LogOnline: Unable to create OnlineSubsystem module Steam

As the warning didn’t appear at my colleague who’s using a Vive I had the feeling the culprit might be connected to Oculus. I killed the Oculus process (OVRServer_x64.exe) in the task manager and voila, we could find each other’s sessions again and were able to connect. Obviously without the OVR Server running the Oculus HMD doesn’t work anymore which is a problem when you are developing a VR prototype!

It seems that recent changes in the Oculus runtime are blocking the Steam OnlineSubsystem Game Sever API.

Did anyone here encounter a similar problem?
Any help would be highly appreciated!!

This message is pretty suspect:

 LogOnline: Warning: STEAM: Failed to initialize Steam, this could be due to a Steam server and client running on the same machine. Try running with -NOSTEAM on the cmdline to disable.

Assuming you are not running 2 Unreals both connected to Steam Online Subsystem, the other possibility is that there are multiple processes listening/sending on one of the Steam ports. I had a problem where some weird Steam Home Beta thing was listening port on 27015, in addition to Steam OSS.

I would suggest that next time this happens, do a “netstat” on all the ports found here. I believe that warning also happens if there are multiple processes messing with one of the ports Steam uses, in addition to Unreal using that port

Thanks so much!!! Netstat was the way to go. TeamViewer was the culprit not Oculus!